Linkage of the structural gene for uroporphyrinogen I synthase to markers on mouse chromosome 9 in a cross between feral and inbred mice.

The Ups locus has been mapped to mouse chromosome 9 in a three-point cross. The observed gene order is centromere-Ups-15-Mpi-1-22-Mod-1. Ups is unlinked to Lv, which encodes the previous enzyme in the heme biosynthesis pathway. Feral mice collected at Skive, Denmark, have been characterized at several biochemical loci; multiple differences from inbred strains make this a useful stock for linkage analysis.